Thermal cycling stability of Cr-N thin films deposited on stainless steel

Stainless steels have several industrial uses, such as in industrial plants, food manufacture, furniture and lighting applications. Hard ceramic coatings are often used to improve steel surface properties. such as hardness, wear resistance and friction. In this work, 150 nm thick Cr-N coatings deposited on AISI 304L by Direct Current (DC) reactive sputtering were studied. Structural and morphological characterizations by X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were carried out before and after thermal cycling at different temperatures. It was found that thermal cycling induces Cr-N oxidation with the progressive formation of Cr2O3 crystallites. Increase of coating surface roughness, cracking and detachment from the substrate occurs for temperatures above 910 K.